Rotary fluid pump or motor with intermeshed spiral walls

ABSTRACT

A fluid pump has two sets of spiral pumping units operating in parallel, one pumping spirally outward and the other spirally inward. Each unit consists of a pair of spiral walls intermeshed between end walls which are pressed towards each other by outlet fluid pressure to obtain good sealing action. The intermeshed spiral walls engage each other along lines of contact which advance spirally, being driven by a rotary drive which, in response to dynamic pumping forces, causes the spiral walls to maintain contact despite wear. The fluid pump can act as a motor when fluid under pressure is forced through the spiral units.

United States Patent 11 1 1111 ,817,

ennett et al. [451 J 1974 [54] ROTARY FLUID PUMP 0R MOTOR WITH 707,8074/1931 France 418/55 INTERMESHED SPIRAL WALLS [75] Inventors: JamesStewart Bennett, 149 Arnold Primary Examiner wimam L Freeh Thomhm; Edwinf f Assistant Examiner.lohn J. Vrablik Hatfield Brampton omano fAttorney, Agent, or Firm-Ridout & Maybee Canada [73] Assignee: saidBennett, by said Hatfield [22] Filed: Dec. 11, 1972 [57] ABSTRACT 21A 1. N l PP 9 314,250 A fluid pump has two sets of spiral pumping unitsoperating in parallel, one pumping spirally outward and [52] US. Cl418/55, 418/57, 418/60 the other spirally inward, Each unit consists ofa pair Int. Cl. F01C 1/02, F036 /00, F046 1/02 of spiral Wallsintermeshed between end walls which F leld of Search 60 are pressedtowards each other by outlet fluid pressure to obtain good sealingaction. The intermeshed spiral [56] References Cited walls engage eachother along lines of contact which UNITED STATES PATENTS advancespirally, being driven by a rotary drive which,

1,906,142 4/1933 Ekelof 418/57 in response to dynamic Pumping forcescauses the 413/57 spiral walls to maintain contact despite wear. Thefluid 4 3 55 pump can act as a motor when fluid under pressure is1,967,957 7/1934 Lucas 3,463,091 8/1969 Delsuc 3,560,119 2/1971 Busch eta1. I: 418/55 forced through the spiral units. 3,600,114 8/1971 Dvoraket a1. 418/55 FOREIGN PATENTS OR APPLICATIONS 25 Claims, 9 DrawingFigures 980,737 1/1951 France 418/55 P'A'TENTEDJun 18 um SHEET 50? v5ROTARY FLUID PUMP OR MOTOR WITH INTERMESHED SPIRAL WALLS BACKGROUND OFTHE INVENTION 1. Field of the Invention This invention relates to afluid pump or motor of the kind havingintermeshed spiral walls.

2. Description of the Prior Art Fluid pumps with a pumping actionproduced by spiral walls have been known for some time but with many ofthe previous pumps the output was not smooth, or the drive was complex,or there were leakage problems. These disadvantages can be overcome withthe present invention.

SUMMARY OF THE INVENTION A relatively smooth pump output can be achievedby operating two spiral pumping units in parallel, one pumping spirallyoutward and the other spirally inward. Fluid outlet pressure is utilizedto reduce internal leakage. A drive, responsive to dynamic pumpingforces, maintains the spiral walls in contact so that wear of the spiralwalls does not cause internal leakage. The operation of the units can bereversed for operation as a fluid motor.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings whichillustrate a preferred embodiment of the invention:

FIG. 1 is a sectional view of a fluid pump; FIG. 2 is a sectional viewalong the line 2-2 of FIG.

FIG. 3 is a sectional view along the line 3-3 of FIG. 1, with a fluidinlet indicated partly in phantom lines;

FIG. 4 is a sectional view along the line 4-4 of FIG. 1, with the fluidinlet indicated in phantom lines;

FIGS. 5, 6, 7 and 8 are schematic views showing successive positions ofspiral walls of a pumping unit during one revolution of its rotarydrive, FIG. 8 showing a position corresponding to FIG. 3; and

FIG. 9 is an exploded view of a modification of part of the pump.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to the schematicFIGS. 5 to 8, these show a stationary housing 1 within which is a pairof identical spiral walls, namely a stationary spiral wall 2 and amovable spiral wall 3. The walls 2, 3 are fitted together approximatelyl80 out of phase with each other. The stationary spiral wall 2 has anaxis 4, and the axis of the spiral wall 3 is offset from the axis of thespiral wall 2 by an amount equal to the radius of a circle 5. The wall 3is oscillated in a circular path so that its axis follows the circle 5in the direction of the arrow thereon, but the 180 relationship of thewalls is maintained, i.e., the wall 3 does not rotate about its axis.The offset of the two axes is such as to cause the walls 2 and 3 tocontact each other along two lines 6 and 7 normal to the paper, and asthe wall 3 moves from the position shown in FIG. 5 through those shownin FIGS. 6, 7 and 8 the lines of contact 6 and 7 move spirally outward,until in the position of FIG. 8 new lines of contact 6 and 7 begin nearthe axes, and these in turn progress spirally outward as the circularoscillation of the wall 3 is continued. These new lines of contact 6',7' are picked up shortly before the lines 6, 7 disappear because eachspiral has slightly more than 1 /2 turns, i.e., each spiral extendsslightly more than 311' radians. As wear occurs it may not be possibleto maintain good contact at all four lines 6, 7 and 6', 7, but while onepair of these lines are in tight contact it is not necessary the othersbe in tight contact. Although spiral walls of greater length than thoseillustrated could be used, with the object of having at all times morethan two lines of contact between the walls, the fabrication of thewalls would require great accuracy.

If fluid is continuouslyadmitted adjacent the axes of the spiral wallsand is confined between these walls, the oscillation of the wall 3causes the fluid to be pumped spirally outward as the lines of contactbetween the walls advance spirally outward.

The pump illustrated in FIGS. 1 to 4 includes two pumping units one ofwhich operates by pumping spirally outward as schematically shown inFIGS. 5 to 8 and the other of which operates by pumping spirally inward.

In FIG. 1, a pump assembly is enclosed between end portions 8, 9 of ahousing, the end portion 9 being held by bolts 10 to a main body member11 on which the end portion 8 removably fits. Stationary end walls 12,13 extending transversely of the housing create a first chamber 14between end wall 12 and end wall 13, and a second chamber 15 between endwall 13 and the end portion 9 of the housing. Thus, end wall 13 forms acommon wall between the two chambers 14, 15, and since, as will beexplained, there is fluid pressure on both sides of this wall, gaskets13a are provided around its periphery. A stationary spiral wall 16 and amovable spiral wall 17 are contained in the first chamber 14 and astationary spiral wall 18 and a movable spiral wall 19 are contained inthe second chamber 15, these walls being seen in transverse section inFIGS. 3 and 4, where it can be seen that the spiral walls of each pairare fitted together out of phase from each other. As can be seen in FIG.1, the spiral walls 16, l7, 18, 19 are each fast along one of theirlongitudinal edges with end walls 12, 20, 13, 21 respectively, the otherlongitudinal edge of each spiral wall 16, 17, 18, 19 bearingfrictionally along the inner surface of end wall 20, 12, 21, 13respectively.

In the position shown in FIGS. 1, 3 and 4, each pair of spiral walls hasfour lines of contact but, as stated above with reference to FIG. 8,this is only a momentary position due to the length of the spiral wallsbeing slightly greater than 1% turns or 31r radians; at most times thereare only two lines of contact between each pair, as indicatedschematically in FIGS. 5, 6 and 7. For the first pair 16, 17, in theposition of FIG. 1, there are four lines of contact 22, 23, 22', 23 andfor the second pair there are four lines of contact 24, 25, 24, 25. Afirst pumping unit is provided by the intermeshed spiral walls l6, l7and their end walls 12, 20, and another pumping unit is provided by thespiral walls l8, l9 and their end walls 13, 21, and as will be seenthese units work in parallel. Spiral wall 17 can be driven to move,relative to spiral wall 16, to advance lines of contact 22', 23 spirallyoutward from a fluid inlet 26. As viewed in FIG. 3, the spiral wall 17is driven so that its axis travels in the circle 5 about the axis 4 ofthe stationary spiral wall 16. Simultaneously, as viewed in FIG. 4, thespiralwall 19 is driven in the same sense as the wall 17, its axistravelling in an identical circle 5 about the axis 4 common tostationary walls 18 and 16. The walls 17 and 19 do not rotate abouttheir axes; they always remain 180 out of phase to the stationary spiralwalls 16 and 18 with which they are intenneshed. The spiral pitch of thespiral walls 18, 19 is opposite to that of the walls 16, 17 (the walls18, 19 being a mirror image of the walls 16, 17), and as spiral wall 19moves relative to spiral wall 18 the lines of contact 24', 25 advancespirally inward from a fluid inlet 28 to a fluid outlet 29. Thus, thefirst pair of spiral walls 16, 17 pump fluid from the inside to theoutside and the second pair of spiral walls 18, 19 pump fluid from theoutside to the inside. The outlet 29 from the second pumping unit ofFIG. 4 leads, as seen in FIG. 1, into the chamber 14 of the firstpumping unit, and it is into this chamber that the first pumping unitdischarges its output, so that the two pumping units have their outletsin parallel, leading to a common outlet pipe connection 30. The inlets26, 28 are similarly in parallel, having a common inlet pipe connection31. Each of the pumping units has a pulsating output, of saw-toothconfiguration if plotted against time, but the parallel arrangement ofthe units produces a smooth (i.e., nonpulsating) output at outlet 30,this output being the sum of two sawtooth outputs. Since the dimensionsof the spiral walls 16, 17, 18, 19 are fixed, the same quantity of fluidis pumped for each oscillation of the pump regardless of the differencebetween inlet and outlet pressures, assuming that an incompressiblefluid is being pumped.

A peripheral sealing portion 32 is added to the movable end wall 21,dividing the second chamber into compartments 33, 34 at opposite sidesof the movable end wall 21, the second spiral pair l8, 19 being incompartment 33. A port 21a through the wall 21 allows the outlet fluidnear the axes of the second pair of spiral walls to flow fromcompartment'33 to compartment 34 where it urges the movable end wall 21and therefore the spiral wall 19 against the end wall 13 of thestationary spiral wall 18. Also, end wall 21 is urged against thelongitudinal edge of spiral wall 18. The outlet fluid in chamber 14(i.e., in the part of the first chamber 14 where the fluid outlet fromthe first pair of spiral walls 16, 17 is located) exerts pressure on endwall of the spiral wall 17, urging the latter against the end wall 12 ofthe stationary spiral wall 16. Thus, leakage is minimized and in factleakage decreases with wear.

In order to oscillate the spiral walls 17, 19 relative to the spiralwalls 16, 18 respectively, in the desired manner, there is provided ashaft 35 which pivots at a ball joint bearing 36 on the axis of thestationary spiral walls 16, 18 and is coupled to spiral walls 17, 19 ata ball joint bearing 37. The shaft 35 is driven, by means describedbelow, in a conical path having its apex at the bearing 36, so that thebearing 37 moves in a circular path. The center of bearing 37 iscoincident with the axes of the movable spiral walls l7, l9 anddescribes the circle 5 of FIGS. 3 and 4 as it moves. Ball joints 36, 37are seated in ball seats 38, 39 respectively. Ball seat 39 is surroundedby a cylindrical sleeve 40 fast with the end wall 21. Ball seat 39 isslidable in sleeve 40 and may be prevented from rotating relativethereto by pins 41. Movable end wall 20 is fast with a sleeve 42telescoped onto the sleeve 40 and slidable thereon, but pins 43 fixed inthe sleeve 40 extend into longitudinal slots 44 in the sleeve 42,preventing relative rotary movement between the sleeves.

Screwed into the end of sleeve 40, and pinned thereto by a radial pin45, is a ring 46, and compressed between the ring 46 and bearing seat 39is a coil spring 47. By reacting against the bearing seat 39 the springpresses the ring 46 and thus the sleeve 40 and end wall 21 and spiralwall 19 in a direction holding the spiral wall 19 against the end wall13, to bear frictionally thereagainst. ln compression between the endwalls 21 and 20 is a weaker spring 48 which, reacting against the wall21 presses the spiral wall 17 against the stationary wall 12 on which itfrictionally bears. The purpose of these springs 47, 48 is to allow fortolerances in the construction of the parts making up the spiral pumpunits, and to minimize leakage during start-up of the pump when there islittle or no outlet fluid pressure to urge the movable spiral walls 17,19 against the stationary end walls 12, 13 respectively.

The ball seat 38 is fixed in a cylindrical hub 50 fastened by studs 51to a cylindrical portion 120 of the transverse wall 12. To provide afluid-tight seal between the wall 12 and the sleeve 40, a bellows 52 isaffixed at one end to the ring 46 and at the other end to a sealing disc53 sandwiched between the wall portion 12a and the hub 50. The sealingbellows 52 around the shaft 35 prevents the fluid being pumped fromentering the area of the bearing 36, and at the same time act as adetent to prevent relative rotation between the stationary end walls 12,13 and the movable end walls 20, 21, and thus between the spiral wallsl6, l7, 18, 19. Thus, as the bearing 37 moves in a circular path, themovable spiral walls 17, 19 oscillate relative to the stationary spiralwalls 16, 18 but do not rotate relative thereto.

A rotary drive is provided by a shaft 54 of a prime mover (not shown).The shaft 54 extends through the housing end portion 8, and has anenlarged drive member or disc 55 having a cylindrical extension 56centered by bearings 57 on the hub 50. The shaft 35 has an end 35a,opposite to that of the ball joint bearing 37, mounted in a bearing 58,and the bearing 58 is located in a guideway or slot 59 in the rotarydrive member 55, as best seen in FIG. 2. The slot 59 has a center line59a which is not quite radial to the drive member 55, the line 59a beingslightly offset from the rotary axis 55a of the drive member. A radialline 55b through the axis 55a and the center line 35b of the shaft makesan angle p with the center line 59a of the slot 59. The bearing 58 isfree to slide along the slot 59, and is biased away from the rotary axis55a by a compression spring 60 in the slot. As the drive member 55rotates, the end 35a of the shaft 35 is driven in a circular path aroundthe axis 55a, so that the shaft 35 is forced to move in a conical pathwith its apex at the bearing 36. With the shaft end 35a urged in thedirection in which it is pressed by the spring 60, the other end 37 ofthe shaft is urged to establish lines of contact between the movablespiral walls 17, 19 and their respective stationary partners 16, 18.

As fluid is pumped, the total dynamic head thereof is transmitted by themovable spiral walls 17, 19 through the shaft 35 to the bearing 58 whichis eccentrically positioned relative to the rotary drive member 55. Asshown in FIG. 2, the transmitted force F due to the dynamic head is atright angles to the radial direction of eccentricity along line 55b.Since the slot 59 is at an angle p to the radial line 55b through thecenter-line of the shaft 35, the force F has a component f which tendsto urge the bearing 58 along the slot 59 towards the outer edge of therotary drive member 55. This component force f is transmitted throughthe shaft 35 to the movable spiral walls l7, 19. As the spiral wallswear, this component force f increases the orbit of the movable spiralwalls l7, 19 so that they are urged both by the spring 60 and by forcef, to maintain contact with the stationary walls 16, 18 respectively.Therefore, wear of the spiral walls does not cause leakage. As wearcontinues it may not be possible to maintain all four lines of contactfor each pair of spiral walls, in the position shown in FIG. 1. However,it is sufficient for the efficient operation of the pump if two lines ofcontact are maintained for each pair. The spring 60 serves to establishlines of contact when the total dynamic head of the pump is low ornegative; as a dynamic head builds up, the force f also builds up.

The thicknesses of the spiral walls is preferably less than the radiusof the circle 5, if the pump is to handle materials carrying solidparticles: if a particle should be caught between a longitudinal edge ofa spiral wall and the end wall against which it bears, movement of thespiral wall by more than twice its own thickness should lead to thereexposure of the particle to the fluid being pumped.

The bellows 52 of FIG. 1 seals the fluid being pumped from lubricatingoil in the shaft system, and should be a metallic bellows to serve as adetent which, while permitting orbital (oscillating) movement of thewalls 17, 19, prevents rotation thereof around their axes. Foreignmatter passing through the pump might cause it to bind, imparting anabnormal torque which would twist the bellows 52 to destruction, and todeal with this problem an alternative detent mechanism is shown in FIG.9, the proportions being somewhat distorted for facility ofillustration. In this arrangement, a fixed ring 53' can be fastened tothe stationary wall portion 12a of FIG. 1, and an orbital ring 40' canbe fixed to the sleeve 40. Between these rings 53', 40 is a detent ring61, and when the mechanism is assembled projections 62 of the detentring 61 fit into radial slots 63 of the fixed ring 53' and projections64 of the detent ring fit into radial slots 65 of the orbital ring 40,the projections fitting snugly in the slots but being slidable radiallythereof. The projections 62 and 64 are on diameters at right angles toeach other, and permit orbital movement of ring 40' while preventingrotation about its axis, thereby preventing rotation of the orbitalmechanism of which it is a part. A bellows 52' can be affixed to therings 40' and 53' by clamping screws 66 which are not exposed to thefluid within the pump, the bellows isolating that fluid from the shaftand driving mechanisms. (A ring, not shown, will be laid over the flange52a of the bellows to clamp it against the ring 40, and the flange 52bwill be clamped between the ring 53' and a stationary casing member, forexample, the wall portion 12a of FIG. 1). Because the bellows need notprovide a detent action, and twisting of the bellows is prevented by thedetent ring 61, the bellows can be made of elastomeric material havinglong fatigue life and good corrosion and wear resistance. The bellowsmay be of large diameter, permitting the use of a large drive shaft andball joints for higher ratings. The bellows preferably has helicalconvolutions, and can be supported by a helical spring (Not shown)within its convolutions to increase its pressure rating.

When the device is operated as a motor the operation heretoforedescribed is reversed. Fluid under pressure is forced into what was theoutlet connection 30. The fluid forces the spiral walls of each pair tomove relative to each other in the opposite direction to that whenoperated as a pump. The inlet pressure (at connection 30) is higher thanthe outlet pressure (at connection 31) and acts on the undersides of theend walls 20, 21 to inhibit leakage. The fluid drives the spiral wallswhich in turn drive what was the drive means when operated as a pump.Since the rotary member 55 is caused to rotate in the opposite directionto that indicated in FIG. 2, the direction of the slot 59 must be at anegative angle p to the radial line 55b through the centreline 35b ofthe shaft 35 (i.e., line 59a must be counterclockwise from line 55b) inorder that the component force f can have the same leakage-inhibitingeffect as it has when the embodiment is operated as a pump.

What we claim as our invention is:

l. A fluid pump or motor comprising a first pair of spiral walls and asecond pair of spiral walls, the walls of each pair being fittedtogether out of phase between end walls perpendicular to the spiralwalls, with two lines of contact between the spiral walls of each pair,means for moving one spiral wall of each pair relative to the otherspiral wall of the same pair, while maintaining said out of phaserelationship, to advance said lines of contact spirally outward, for thefirst pair, from a fluid inlet to a fluid outlet, and spirally inward,for the second pair, from a fluid inlet to a fluid outlet, whereby fluidflows spirally outward between the first pair and spirally inwardbetween the second pair, the fluid inlets being in parallel and thefluid outlets being in parallel whereby the total flow through the pumpor motor is the sum of said spirally outward and inward flows, the sizesand configurations of the first and second pairs of walls beingsubstantially identical whereby said sum is substantially nonpulsating.

2. A fluid pump or motor as claimed in claim 1 wherein each spiral wallextends approximately 3n radians.

3. A fluid pump as claimed in claim 1 wherein the walls of each pair arefitted together approximately out of phase.

4. A fluid pump or motor as claimed in claim 1 wherein each spiral wallhas two longitudinal edges, one longitudinal edge of one spiral wall ofeach pair being fast with one end wall, the other longitudinal edge ofthe latter spiral wall bearing frictionally along an opposite end wall,one longitudinal edge of the other spiral wall of the pair being fastwith said opposite end wall and the other longitudinal edge of thelatter spiral wall bearing frictionally along said one end wall.

5. A fluid pump or motor as claimed in claim 4 wherein one spiral walland end wall of each pair are stationary, and the other spiral wall andend wall of the pair are movable by said moving means.

6. A fluid pump or motor as claimed in claim 5 wherein the moving meanscomprise a shaft pivoted for movement in a conical path, rotary meansfor driving the shaft in said conical path, and means coupling the shaftwith the movable wall of each pair.

7. A fluid pump or motor as claimed in claim 6 wherein the couplingmeans comprise a bearing into which oneend of the shaft extends and onwhich the movable spiral walls are driven in circular paths of the samesize.

8. A fluid pump or motor as claimed in claim wherein the movable one ofthe end walls of each pair has an outer surface subjected to thepressure at the fluid outlet whereby it is fluid pressed towards thestationary end wall of the same pair.

9. A fluid pump or motor as claimed in claim 8 wherein, for the secondpair of spiral walls whose lines of contact advance spirally inward froma fluid inlet to a fluid outlet, the movable end wall has a port throughwhich outlet fluid can flow to exert pressure against the outer surfaceof said end wall, said end wall having an inner surface and a peripheralsealing portion that confines inlet fluid pressure to said innersurface.

10. A fluid pump or motor as claimed in claim 8 and including springmeans urging the movable end wall of each pair towards the stationaryend wall.

11. A fluid pump or motor comprising a pair of substantially identicalspiral walls fitted together approximately 180 out of phase between endwalls perpendicular to the spiral walls, with two lines of contactbetween the spiral walls, means for moving one spiral wall relative tothe other, while maintaining said phase relationship, to advance thesaid lines of contact spirally from a fluid inlet to a fluid outlet,said means comprising a shaft pivoted for movement in a conical path,means coupling the shaft with said one of the spiral walls, a rotarydrive member for driving the shaft in said conical path, the rotarydrive member having an outer edge and a guideway extending towards saidouter edge and engaging the shaft, the shaft having a center lineintersected by a radius of the rotary drive member, and the guidewaybeing at an angle to said radius whereby a dynamic force on the shaftnormal to said radius has a component along the guideway urging theshaft to move in a direction along the guideway to press together thespiral walls.

12. A fluid pump or motor as claimed in claim 11 wherein one of the endwalls has an outer surface subjected to the pressure at the fluid outletwhereby it is fluid pressed towards the other end wall.

13. A fluid pump or motor as claimed in claim 11 wherein the guidewaycomprises a slot, and a spring in the slot urges the shaft .in saiddirection along the slot,

14. A fluid pump or motor as claimed in claim 13 wherein the shaft islocated in a bearing located in and slidable in the slot, the bearingbeing pressed in said direction by the spring.

15. A fluid pump or motor as claimed in claim 11 wherein the meanscoupling the shaft with said one of the spiral walls comprise a bearinginto which one end of the shaft extends and on which said one of thespiral walls is driven in a circular path.

16. A fluid pump or motor as claimed in claim 15 wherein said one of thespiral walls is fast with one of the end walls and is urged to bearfrictionally against the other end wall by a spring supported by saidbearing.

17. A fluid pump or motor as claimed in claim 15 and including anotherpair of substantially identical spiral walls also fitted togetherapproximately 180 out of phase between end walls perpendicular thereto,and with two lines of contact between the spiral walls of said otherpair, the spiral walls of said other pair being of opposite pitch to thefirst mentioned pair, one of the spiral walls of said other pair beingdriven by said bearing in a circular path, in the same sense as thedriven spiral wall of the first mentioned pair, to advance the lines ofcontact of said other pair spirally from a fluid inlet to a fluidoutlet, one of the spiral walls of each pair being stationary.

18. A fluid pump or motor as claimed inclaim 15 wherein the shaft ispivoted, for movement in said conical path, in a bearing located betweensaid one end of the shaft and said rotary drive member, and a flexiblebellows around the shaft isolates the shaft and bearings from the fluidbeing pumped.

19. A fluid pump or motor as claimed in claim 18 wherein said phaserelationship is maintained by a detent ring within the bellows whichprevents twisting of the bellows during said relative movement of thespiral walls.

20. A fluid pump or motor comprising a first pair of spiral wallssubstantially identical to each other, and a second pair of spiral wallssubstantially identical to each other, the walls of each pair beingfitted together approximately out of phase between end wallsperpendicular to the spiral walls, with two lines of contact between thespiral walls of each pair, means for moving one spiral wall of each pairrelative to the other spiral wall of the same pair, while maintainingsaid phase relationship, to advance said lines of contact spirallyoutward, for the first pair, from a fluid inlet to a fluid outlet, andspirally inward, for the second pair, from a fluid inlet to a fluidoutlet, the inlets being in parallel and the fluid outlets being inparallel, each spiral wall having two longitudinal edges, onelongitudinal edge of one spiral wall of each pair being fast with oneend wall, the other longitudinal edge of the latter spiral wall bearingfrictionally along an opposite end wall, one longitudinal edge of theother spiral wall of the pair being fast with said opposite end wall andthe other longitudinal edge of the latter spiral wall bearingfrictionally along said one end wall, one spiral wall and end wall ofeach pair being stationary, and the other spiral wall and end wall ofeach pair being movable by said moving means, the movable spiral wallsbeing coaxially arranged on a common bearing of said moving means, thestationary end wall of the first pair being a wall of a first chambersurrounding the movable end wall and the spiral walls of the first pair,the fluid inlet for the first pair being through said stationary chamberwall near the axes of the spiral walls, and the advance of the lines ofcontact of the first pair spirally outward delivering fluid to part ofsaid surrounding first chamber where the fluid outlet for the first pairis located and where the outlet fluid pressure urges the movable endwall of the first pair towards said stationary chamber wall, thestationary end wall of the second pair being a common wall of the firstchamber and of a second chamber surrounding the movable end wall and thespiral walls of the second pair, the movable end wall of the second pairhaving a peripheral portion that divides the second chamber into twocompartments at opposite sides of the movable end wall of the secondpair, the second pair of spiral walls being in one of said compartments,the fluid outlet for the second pair being from said one compartmentthrough said common wall into the first chamber near the axes of thespiral walls, the fluid inlet for the second pair being into said onecompartment and the advance of the lines of contact of the second pairdelivering fluid spirally inward from said fluid inlet of the secondpair to said fluid outlet thereof, the movable end wall of the secondpair having a port through which outlet fluid can flow to the other ofsaid compartments where it urges the movable end wall of the second pairtowards said common wall.

21. A fluid pump or motor comprising a first pair of spiral wallssubstantially identical to each other, and a second pair of spiral wallssubstantially identical to each other, the walls of each pair beingfitted together approximately 180 out of phase between end wallsperpendicular to the spiral walls, with two lines of contact between thespiral walls of each pair, means for moving one spiral wall of each pairrelative to the other spiral wall of the same pair, while maintainingsaid phase relationship, to advance said lines of contact spirallyoutward, for the first pair, from a fluid inlet to a fluid outlet, andspirally inward, for the second pair, from a fluid inlet to a fluidoutlet, the inlets being in parallel and the fluid outlets being inparallel, each spiral wall having two longitudinal edges, onelongitudinal edge of one spiral wall of each pair being fast with oneend wall, the other longitudinal edge of the latter spiral wall bearingfrictionally along an opposite end wall, one longitudinal edge of theother spiral wall of the pair being fast with said opposite end wall andthe other longitudinal edge of the latter spiral wall bearingfrictionally along said one end wall, one spiral wall and end wall ofeach pair being stationary, and the other spiral wall and end wall ofeach pair being movable by said moving means; the moving meanscomprising a shaft pivoted for movement in a conical path, rotary meansfor driving the shaft in said conical path, and means coupling the shaftwith the movable wall of each pair, the coupling means comprising abearing into which one end of the shaft extends and on which the movablespiral walls are driven in circular paths of the same size; a firstspring reacting against the bearing and pressing one of the movablespiral walls against the end wall on which it frictionally bears, and asecond spring reacting against the movable end wall which is fast withsaid one of the movable spiral walls and pressing the other of themovable spiral walls against the end wall on which it frictionallybears.

22. A fluid pump or motor comprising a first pair of spiral wallssubstantially identical to each other, and a second pair of spiral wallssubstantially identical to each other, the walls of each pair beingfitted together approximately 180 out of phase between end wallsperpendicular to the spiral walls, with two lines of contact between thespiral walls of each pair, means for moving one spiral wall of each pairrelative to the other spiral wall of the same pair, while maintainingsaid phase relationship, to advance said lines of contact spirallyoutward, for the first pair, from a fluid inlet to a fluid outlet, andspirally inward, for the second pair, from a fluid inlet to a fluidoutlet, the inlets being in parallel and the fluid outlets being inparallel, each spiral wall having two longitudinal edges, onelongitudinal edge of one spiral wall of each pair being fast with oneend wall, the other longitudinal edge of the latter spiral wall bearingfrictionally along an opposite end wall, one longitudinal edge of theother spiral wall of the pair being fast with said opposite end wall andthe other longitudinal edge of the latter spiral wall bearingfrictionally along said one end wall, one spiral wall and end wall ofeach pair being stationary, and the other spiral wall and end wall ofeach pair being movable by said moving means, the moving meanscomprising a shaft pivoted for movement in a conical path, rotary meansfor driving the shaft in said conical path, and means coupling the shaftwith the movable wall of each pair, the rotary means for driving theshaft comprising a rotary drive member having an outer edge and aguideway extending towards said outer edge and engaging the shaft, theshaft having a center line intersected by a radius of the rotary drivemember, and the guideway being at an angle to said radius whereby adynamic force on the shaft normal to said radius has a compo nent alongthe guideway urging the shaft to move in a direction along the guidewayto press together the spiral walls of each pair at their lines ofcontact.

23. A fluid pump or motor comprising a pair of substantially identicalspiral walls fitted together out of phase between end wallsperpendicular to the spiral walls, with two lines of contact between thespiral walls, means for moving one spiral wall relative to the other,while maintaining said out of phase relationship, to advance the saidlines of contact spirally from a fluid inlet to a fluid outlet, one ofthe end walls having an outer surface subjected to the pressure at thefluid outlet whereby it is fluid pressed towards the other end wall,each spiral wall having two longitudinal edges, one longitudinal edge ofeach spiral wall being fast with one end wall, the other longitudinaledge bearing frictionally along the other end wall, one spiral wall andend wall being stationary and the other spiral wall and end wall beingmovable by said moving means, the stationary wall being a wall of achamber surrounding the movable end wall and the spiral walls, themovable end wall having a peripheral portion that sealingly divides thechamber into two compartments at opposite sides of the movable end wall,the advance of said lines of contact delivering fluid spirally inward inone of said compartments from the inlet to the outlet, the movable endwall having a port through which outlet fluid can flow to the other ofsaid compartments where it urges 1 the movable end wall towards thestationary wall.

24. A fluid pump or motor comprising a pair of substantially identicalspiral walls fitted together approximately 180 out of phase between endwalls perpendicular to the spiral walls, with two lines of contactbetween the spiral walls, means for moving one spiral wall relative tothe other, while maintaining said phase relationship, to advance thesaid lines of contact spirally from a fluid inlet to a fluid outlet, oneof the end walls having an outer surface subjected to the pressure atthe fluid outlet whereby it is fluid pressed towards the other end wall,each spiral wall having two longitudinal edges, one longitudinal edge ofeach spiral wall being fast with one end wall, the other longitudinaledge bearing frictionally along the other end wall, one spiral wall andend wall being stationary and the other spiral wall and end wall beingmovable bysaid moving means, said moving means comprise a shaft pivotedfor movement in a conical path, means coupling the shaft with themovable spiral wall, a rotary drive member for driving the shaft in saidconical path, the rotary drive member having an outer edge and aguideway extending towards said outer edge and engaging the shaft, theshaft having a center line intersected by a radius of the rotary drivemember, and the guideway being at an 25. A fluid pump or motorcomprising a first pair of spiral walls substantially identical to eachother, and a second pair of spiral walls substantially identical to eachother, the walls of each pair being fitted together approximately 180out of phase between end walls perpendicular to the spiral walls, withtwo lines of contact between the spiral walls of each pair, means formoving one spiral wall of each pair relative to the other spiral wall ofthe same pair, while maintaining said phase relationship, to advancesaid lines of contact spirally outward, for the first pair, from a fluidinlet to a fluid outlet, and spirally inward, for the second pair, froma fluid inlet to a fluid outlet, the inlets being in parallel and thefluid outlets being in parallel, the moving means comprising a shaftpivoted for movement in a conical path, rotary means for driving theshaft in said conical path, and means coupling the shaft with a movablewall of each pair, the rotary means for driving the shaft comprising arotary drive member having an outer edge and a guideway extendingtowards said outer edge and engaging the shaft, the shaft having acenter line intersected by a radius of the rotary drive member, and theguideway being at an angle to said radius whereby a dynamic force on theshaft normal to said radius has a component along the guideway urgingthe shaft to move in a direction along the guideway to press togetherthe spiral walls of each pair at their lines of contact.

1. A fluid pump or motor comprising a first pair of spiral walls and asecond pair of spiral walls, the walls of each pair being fittedtogether out of phase between end walls perpendicular to the spiralwalls, with two lines of contact between the spiral walls of each pair,means for moving one spiral wall of each pair relative to the otherspiral wall of the same pair, while maintaining said out of phaserelationship, to advance said lines of contact spirally outward, for thefirst pair, from a fluid inlet to a fluid outlet, and spirally inward,for the second pair, from a fluid inlet to a fluid outlet, whereby fluidflows spirally outward between the first pair and spirally inwardbetween the second pair, the fluid inlets being in parallel and thefluid outlets being in parallel whereby the total flow through the pumpor motor is the sum of said spirally outward and inward flows, the sizesand configurations of the first and second pairs of walls beingsubstantially identical whereby said sum is substantially nonpulsating.2. A fluid pump or motor as claimed in claim 1 wherein each spiral wallextends approximately 3 pi radians.
 3. A fluid pump as claimed in claim1 wherein the walls of each pair are fitted together approximately 180*out of phase.
 4. A fluid pump or motor as claimed in claim 1 whereineach spiral wall has two longitudinal edges, one longitudinal edge ofone spiral wall of each pair being fast with one end wall, the otherlongitudinal edge of the latter spiral wall bearing frictionally alongan opposite end wall, one longitudinal edge of the other spiral wall ofthe pair being fast with said opposite end wall and the otherlongitudinal edge of the latter spiral wall bearing frictionally alongsaid one end wall.
 5. A fluid pump or motor as claimed in claim 4wherein one spiral wall and end wall of each pair are stationary, andthe other spiral wall and end wall of the pair are movable by saidmoving means.
 6. A fluid pump or motor as claimed in claim 5 wherein themoving means comprise a shaft pivoted for movement in a conical path,rotary means for driving the shaft in said conical path, and meanscoupling the shaft with the movable wall of each pair.
 7. A fluid pumpor motor as claimed in claim 6 wherein the coupling means comprise abearing into which one end of the shaft extends and on which the movablespiral walls are driven in circular paths of the same size.
 8. A fluidpump or motor as claimed in claim 5 wherein the movable one of the endwalls of each pair has an outer surface subjected to the pressure at thefluid outlet whereby it is fluid pressed towards the stationary end wallof the same pair.
 9. A fluid pump or motor as claimed in claim 8wherein, for the second pair of spiral walls whose lines of contactadvance spirally inward from a fluid inlet to a fluid outlet, themovable end wall has a port through which outlet fluid can flow to exertpressure against the outer surface of said end wall, said end wallhaving an inner surface and a peripheral sealing portion that confinesinlet fluid pressure to said inner surface.
 10. A fluid pump or motor asclaimed in claim 8 and including spring means urging the movable endwall of each pair towards the stationary end wall.
 11. A fluid pump ormotor comprising a pair of substantially identical spiral walls fittedtogether approximately 180* out of phase between end walls perpendicularto the spiral walls, with two lines of contact between the spiral walls,means for moving one spiral wall relative to the other, whilemaintaining said phase relationship, to advance the said lines ofcontact spirally from a fluid inlet to a fluid outlet, said meanscomprising a shaft pivoted for movement in a conical path, meanscoupling the shaft with said one of the spiral walls, a rotary drivemember for driving the shaft in said coniCal path, the rotary drivemember having an outer edge and a guideway extending towards said outeredge and engaging the shaft, the shaft having a center line intersectedby a radius of the rotary drive member, and the guideway being at anangle to said radius whereby a dynamic force on the shaft normal to saidradius has a component along the guideway urging the shaft to move in adirection along the guideway to press together the spiral walls.
 12. Afluid pump or motor as claimed in claim 11 wherein one of the end wallshas an outer surface subjected to the pressure at the fluid outletwhereby it is fluid pressed towards the other end wall.
 13. A fluid pumpor motor as claimed in claim 11 wherein the guideway comprises a slot,and a spring in the slot urges the shaft in said direction along theslot.
 14. A fluid pump or motor as claimed in claim 13 wherein the shaftis located in a bearing located in and slidable in the slot, the bearingbeing pressed in said direction by the spring.
 15. A fluid pump or motoras claimed in claim 11 wherein the means coupling the shaft with saidone of the spiral walls comprise a bearing into which one end of theshaft extends and on which said one of the spiral walls is driven in acircular path.
 16. A fluid pump or motor as claimed in claim 15 whereinsaid one of the spiral walls is fast with one of the end walls and isurged to bear frictionally against the other end wall by a springsupported by said bearing.
 17. A fluid pump or motor as claimed in claim15 and including another pair of substantially identical spiral wallsalso fitted together approximately 180* out of phase between end wallsperpendicular thereto, and with two lines of contact between the spiralwalls of said other pair, the spiral walls of said other pair being ofopposite pitch to the first mentioned pair, one of the spiral walls ofsaid other pair being driven by said bearing in a circular path, in thesame sense as the driven spiral wall of the first mentioned pair, toadvance the lines of contact of said other pair spirally from a fluidinlet to a fluid outlet, one of the spiral walls of each pair beingstationary.
 18. A fluid pump or motor as claimed in claim 15 wherein theshaft is pivoted, for movement in said conical path, in a bearinglocated between said one end of the shaft and said rotary drive member,and a flexible bellows around the shaft isolates the shaft and bearingsfrom the fluid being pumped.
 19. A fluid pump or motor as claimed inclaim 18 wherein said phase relationship is maintained by a detent ringwithin the bellows which prevents twisting of the bellows during saidrelative movement of the spiral walls.
 20. A fluid pump or motorcomprising a first pair of spiral walls substantially identical to eachother, and a second pair of spiral walls substantially identical to eachother, the walls of each pair being fitted together approximately 180*out of phase between end walls perpendicular to the spiral walls, withtwo lines of contact between the spiral walls of each pair, means formoving one spiral wall of each pair relative to the other spiral wall ofthe same pair, while maintaining said phase relationship, to advancesaid lines of contact spirally outward, for the first pair, from a fluidinlet to a fluid outlet, and spirally inward, for the second pair, froma fluid inlet to a fluid outlet, the inlets being in parallel and thefluid outlets being in parallel, each spiral wall having twolongitudinal edges, one longitudinal edge of one spiral wall of eachpair being fast with one end wall, the other longitudinal edge of thelatter spiral wall bearing frictionally along an opposite end wall, onelongitudinal edge of the other spiral wall of the pair being fast withsaid opposite end wall and the other longitudinal edge of the latterspiral wall bearing frictionally along said one end wall, one spiralwall and end wall of each pair being stationary, and the other spiralwall and end walL of each pair being movable by said moving means, themovable spiral walls being coaxially arranged on a common bearing ofsaid moving means, the stationary end wall of the first pair being awall of a first chamber surrounding the movable end wall and the spiralwalls of the first pair, the fluid inlet for the first pair beingthrough said stationary chamber wall near the axes of the spiral walls,and the advance of the lines of contact of the first pair spirallyoutward delivering fluid to part of said surrounding first chamber wherethe fluid outlet for the first pair is located and where the outletfluid pressure urges the movable end wall of the first pair towards saidstationary chamber wall, the stationary end wall of the second pairbeing a common wall of the first chamber and of a second chambersurrounding the movable end wall and the spiral walls of the secondpair, the movable end wall of the second pair having a peripheralportion that divides the second chamber into two compartments atopposite sides of the movable end wall of the second pair, the secondpair of spiral walls being in one of said compartments, the fluid outletfor the second pair being from said one compartment through said commonwall into the first chamber near the axes of the spiral walls, the fluidinlet for the second pair being into said one compartment and theadvance of the lines of contact of the second pair delivering fluidspirally inward from said fluid inlet of the second pair to said fluidoutlet thereof, the movable end wall of the second pair having a portthrough which outlet fluid can flow to the other of said compartmentswhere it urges the movable end wall of the second pair towards saidcommon wall.
 21. A fluid pump or motor comprising a first pair of spiralwalls substantially identical to each other, and a second pair of spiralwalls substantially identical to each other, the walls of each pairbeing fitted together approximately 180* out of phase between end wallsperpendicular to the spiral walls, with two lines of contact between thespiral walls of each pair, means for moving one spiral wall of each pairrelative to the other spiral wall of the same pair, while maintainingsaid phase relationship, to advance said lines of contact spirallyoutward, for the first pair, from a fluid inlet to a fluid outlet, andspirally inward, for the second pair, from a fluid inlet to a fluidoutlet, the inlets being in parallel and the fluid outlets being inparallel, each spiral wall having two longitudinal edges, onelongitudinal edge of one spiral wall of each pair being fast with oneend wall, the other longitudinal edge of the latter spiral wall bearingfrictionally along an opposite end wall, one longitudinal edge of theother spiral wall of the pair being fast with said opposite end wall andthe other longitudinal edge of the latter spiral wall bearingfrictionally along said one end wall, one spiral wall and end wall ofeach pair being stationary, and the other spiral wall and end wall ofeach pair being movable by said moving means; the moving meanscomprising a shaft pivoted for movement in a conical path, rotary meansfor driving the shaft in said conical path, and means coupling the shaftwith the movable wall of each pair, the coupling means comprising abearing into which one end of the shaft extends and on which the movablespiral walls are driven in circular paths of the same size; a firstspring reacting against the bearing and pressing one of the movablespiral walls against the end wall on which it frictionally bears, and asecond spring reacting against the movable end wall which is fast withsaid one of the movable spiral walls and pressing the other of themovable spiral walls against the end wall on which it frictionallybears.
 22. A fluid pump or motor comprising a first pair of spiral wallssubstantially identical to each other, and a second pair of spiral wallssubstantially identical to each other, the walls of each pair beingfitted together approXimately 180* out of phase between end wallsperpendicular to the spiral walls, with two lines of contact between thespiral walls of each pair, means for moving one spiral wall of each pairrelative to the other spiral wall of the same pair, while maintainingsaid phase relationship, to advance said lines of contact spirallyoutward, for the first pair, from a fluid inlet to a fluid outlet, andspirally inward, for the second pair, from a fluid inlet to a fluidoutlet, the inlets being in parallel and the fluid outlets being inparallel, each spiral wall having two longitudinal edges, onelongitudinal edge of one spiral wall of each pair being fast with oneend wall, the other longitudinal edge of the latter spiral wall bearingfrictionally along an opposite end wall, one longitudinal edge of theother spiral wall of the pair being fast with said opposite end wall andthe other longitudinal edge of the latter spiral wall bearingfrictionally along said one end wall, one spiral wall and end wall ofeach pair being stationary, and the other spiral wall and end wall ofeach pair being movable by said moving means, the moving meanscomprising a shaft pivoted for movement in a conical path, rotary meansfor driving the shaft in said conical path, and means coupling the shaftwith the movable wall of each pair, the rotary means for driving theshaft comprising a rotary drive member having an outer edge and aguideway extending towards said outer edge and engaging the shaft, theshaft having a center line intersected by a radius of the rotary drivemember, and the guideway being at an angle to said radius whereby adynamic force on the shaft normal to said radius has a component alongthe guideway urging the shaft to move in a direction along the guidewayto press together the spiral walls of each pair at their lines ofcontact.
 23. A fluid pump or motor comprising a pair of substantiallyidentical spiral walls fitted together out of phase between end wallsperpendicular to the spiral walls, with two lines of contact between thespiral walls, means for moving one spiral wall relative to the other,while maintaining said out of phase relationship, to advance the saidlines of contact spirally from a fluid inlet to a fluid outlet, one ofthe end walls having an outer surface subjected to the pressure at thefluid outlet whereby it is fluid pressed towards the other end wall,each spiral wall having two longitudinal edges, one longitudinal edge ofeach spiral wall being fast with one end wall, the other longitudinaledge bearing frictionally along the other end wall, one spiral wall andend wall being stationary and the other spiral wall and end wall beingmovable by said moving means, the stationary wall being a wall of achamber surrounding the movable end wall and the spiral walls, themovable end wall having a peripheral portion that sealingly divides thechamber into two compartments at opposite sides of the movable end wall,the advance of said lines of contact delivering fluid spirally inward inone of said compartments from the inlet to the outlet, the movable endwall having a port through which outlet fluid can flow to the other ofsaid compartments where it urges the movable end wall towards thestationary wall.
 24. A fluid pump or motor comprising a pair ofsubstantially identical spiral walls fitted together approximately 180*out of phase between end walls perpendicular to the spiral walls, withtwo lines of contact between the spiral walls, means for moving onespiral wall relative to the other, while maintaining said phaserelationship, to advance the said lines of contact spirally from a fluidinlet to a fluid outlet, one of the end walls having an outer surfacesubjected to the pressure at the fluid outlet whereby it is fluidpressed towards the other end wall, each spiral wall having twolongitudinal edges, one longitudinal edge of each spiral wall being fastwith one end wall, the other longitudinal edge bearing frictionallyalong the other enD wall, one spiral wall and end wall being stationaryand the other spiral wall and end wall being movable by said movingmeans, said moving means comprise a shaft pivoted for movement in aconical path, means coupling the shaft with the movable spiral wall, arotary drive member for driving the shaft in said conical path, therotary drive member having an outer edge and a guideway extendingtowards said outer edge and engaging the shaft, the shaft having acenter line intersected by a radius of the rotary drive member, and theguideway being at an angle to said radius whereby a dynamic force on theshaft normal to said radius has a component along the guideway urgingthe shaft to move in a direction along the guideway to press togetherthe spiral walls at their lines of contact.
 25. A fluid pump or motorcomprising a first pair of spiral walls substantially identical to eachother, and a second pair of spiral walls substantially identical to eachother, the walls of each pair being fitted together approximately 180*out of phase between end walls perpendicular to the spiral walls, withtwo lines of contact between the spiral walls of each pair, means formoving one spiral wall of each pair relative to the other spiral wall ofthe same pair, while maintaining said phase relationship, to advancesaid lines of contact spirally outward, for the first pair, from a fluidinlet to a fluid outlet, and spirally inward, for the second pair, froma fluid inlet to a fluid outlet, the inlets being in parallel and thefluid outlets being in parallel, the moving means comprising a shaftpivoted for movement in a conical path, rotary means for driving theshaft in said conical path, and means coupling the shaft with a movablewall of each pair, the rotary means for driving the shaft comprising arotary drive member having an outer edge and a guideway extendingtowards said outer edge and engaging the shaft, the shaft having acenter line intersected by a radius of the rotary drive member, and theguideway being at an angle to said radius whereby a dynamic force on theshaft normal to said radius has a component along the guideway urgingthe shaft to move in a direction along the guideway to press togetherthe spiral walls of each pair at their lines of contact.